/*
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    All rights reserved

    VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

    ***************************************************************************
     *                                                                       *
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    ***************************************************************************

    This file is part of the FreeRTOS distribution.

    FreeRTOS is free software; you can redistribute it and/or modify it under
    the terms of the GNU General Public License (version 2) as published by the
    Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.

    >>! NOTE: The modification to the GPL is included to allow you to distribute
    >>! a combined work that includes FreeRTOS without being obliged to provide
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    1 tab == 4 spaces!

    ***************************************************************************
     *                                                                       *
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    ***************************************************************************

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*/

/* Scheduler includes. */
#include "FreeRTOS.h"
#include "task.h"

/* Hardware includes. */
#include <microblaze_exceptions_i.h>
#include <microblaze_exceptions_g.h>

/* The Xilinx library defined exception entry point stacks a number of
registers.  These definitions are offsets from the stack pointer to the various
stacked register values. */
#define portexR3_STACK_OFFSET	4
#define portexR4_STACK_OFFSET	5
#define portexR5_STACK_OFFSET	6
#define portexR6_STACK_OFFSET	7
#define portexR7_STACK_OFFSET	8
#define portexR8_STACK_OFFSET	9
#define portexR9_STACK_OFFSET	10
#define portexR10_STACK_OFFSET	11
#define portexR11_STACK_OFFSET	12
#define portexR12_STACK_OFFSET	13
#define portexR15_STACK_OFFSET	16
#define portexR18_STACK_OFFSET  19
#define portexMSR_STACK_OFFSET	20
#define portexR19_STACK_OFFSET  -1

/* This is defined to equal the size, in bytes, of the stack frame generated by
the Xilinx standard library exception entry point.  It is required to determine
the stack pointer value prior to the exception being entered. */
#define portexASM_HANDLER_STACK_FRAME_SIZE 84UL

/* The number of bytes a MicroBlaze instruction consumes. */
#define portexINSTRUCTION_SIZE	4

/* Exclude this entire file if the MicroBlaze is not configured to handle
exceptions, or the application defined configuration constant
configINSTALL_EXCEPTION_HANDLERS is not set to 1. */
#if ( MICROBLAZE_EXCEPTIONS_ENABLED == 1 ) && ( configINSTALL_EXCEPTION_HANDLERS == 1 )

/* This variable is set in the exception entry code, before
vPortExceptionHandler is called. */
uint32_t *pulStackPointerOnFunctionEntry = NULL;

/* This is the structure that is filled with the MicroBlaze context as it
existed immediately prior to the exception occurrence.  A pointer to this
structure is passed into the vApplicationExceptionRegisterDump() callback
function, if one is defined. */
static xPortRegisterDump xRegisterDump;

/* This is the FreeRTOS exception handler that is installed for all exception
types.  It is called from vPortExceptionHanlderEntry() - which is itself defined
in portasm.S. */
void vPortExceptionHandler( void *pvExceptionID );
extern void vPortExceptionHandlerEntry( void *pvExceptionID );

/*-----------------------------------------------------------*/

/* vApplicationExceptionRegisterDump() is a callback function that the 
application can optionally define to receive a populated xPortRegisterDump
structure.  If the application chooses not to define a version of 
vApplicationExceptionRegisterDump() then this weekly defined default 
implementation will be called instead. */
extern void vApplicationExceptionRegisterDump( xPortRegisterDump *xRegisterDump ) __attribute__((weak));
void vApplicationExceptionRegisterDump( xPortRegisterDump *xRegisterDump )
{
	( void ) xRegisterDump;

	for( ;; )
	{
		portNOP();
	}
}
/*-----------------------------------------------------------*/

void vPortExceptionHandler( void *pvExceptionID )
{
extern void *pxCurrentTCB;

	/* Fill an xPortRegisterDump structure with the MicroBlaze context as it
	was immediately before the exception occurrence. */
	
	/* First fill in the name and handle of the task that was in the Running 
	state when the exception occurred. */
	xRegisterDump.xCurrentTaskHandle = pxCurrentTCB;
	xRegisterDump.pcCurrentTaskName = pcTaskGetTaskName( NULL );

	configASSERT( pulStackPointerOnFunctionEntry );

	/* Obtain the values of registers that were stacked prior to this function
	being called, and may have changed since they were stacked. */
	xRegisterDump.ulR3 = pulStackPointerOnFunctionEntry[ portexR3_STACK_OFFSET ];
	xRegisterDump.ulR4 = pulStackPointerOnFunctionEntry[ portexR4_STACK_OFFSET ];
	xRegisterDump.ulR5 = pulStackPointerOnFunctionEntry[ portexR5_STACK_OFFSET ];
	xRegisterDump.ulR6 = pulStackPointerOnFunctionEntry[ portexR6_STACK_OFFSET ];
	xRegisterDump.ulR7 = pulStackPointerOnFunctionEntry[ portexR7_STACK_OFFSET ];
	xRegisterDump.ulR8 = pulStackPointerOnFunctionEntry[ portexR8_STACK_OFFSET ];
	xRegisterDump.ulR9 = pulStackPointerOnFunctionEntry[ portexR9_STACK_OFFSET ];
	xRegisterDump.ulR10 = pulStackPointerOnFunctionEntry[ portexR10_STACK_OFFSET ];
	xRegisterDump.ulR11 = pulStackPointerOnFunctionEntry[ portexR11_STACK_OFFSET ];
	xRegisterDump.ulR12 = pulStackPointerOnFunctionEntry[ portexR12_STACK_OFFSET ];
	xRegisterDump.ulR15_return_address_from_subroutine = pulStackPointerOnFunctionEntry[ portexR15_STACK_OFFSET ];
	xRegisterDump.ulR18 = pulStackPointerOnFunctionEntry[ portexR18_STACK_OFFSET ];
	xRegisterDump.ulR19 = pulStackPointerOnFunctionEntry[ portexR19_STACK_OFFSET ];
	xRegisterDump.ulMSR = pulStackPointerOnFunctionEntry[ portexMSR_STACK_OFFSET ];
	
	/* Obtain the value of all other registers. */
	xRegisterDump.ulR2_small_data_area = mfgpr( R2 );
	xRegisterDump.ulR13_read_write_small_data_area = mfgpr( R13 );
	xRegisterDump.ulR14_return_address_from_interrupt = mfgpr( R14 );
	xRegisterDump.ulR16_return_address_from_trap = mfgpr( R16 );
	xRegisterDump.ulR17_return_address_from_exceptions = mfgpr( R17 );
	xRegisterDump.ulR20 = mfgpr( R20 );
	xRegisterDump.ulR21 = mfgpr( R21 );
	xRegisterDump.ulR22 = mfgpr( R22 );
	xRegisterDump.ulR23 = mfgpr( R23 );
	xRegisterDump.ulR24 = mfgpr( R24 );
	xRegisterDump.ulR25 = mfgpr( R25 );
	xRegisterDump.ulR26 = mfgpr( R26 );
	xRegisterDump.ulR27 = mfgpr( R27 );
	xRegisterDump.ulR28 = mfgpr( R28 );
	xRegisterDump.ulR29 = mfgpr( R29 );
	xRegisterDump.ulR30 = mfgpr( R30 );
	xRegisterDump.ulR31 = mfgpr( R31 );
	xRegisterDump.ulR1_SP = ( ( uint32_t ) pulStackPointerOnFunctionEntry ) + portexASM_HANDLER_STACK_FRAME_SIZE;
	xRegisterDump.ulEAR = mfear();
	xRegisterDump.ulESR = mfesr();
	xRegisterDump.ulEDR = mfedr();
	
	/* Move the saved program counter back to the instruction that was executed
	when the exception occurred.  This is only valid for certain types of
	exception. */
	xRegisterDump.ulPC = xRegisterDump.ulR17_return_address_from_exceptions - portexINSTRUCTION_SIZE;

	#if XPAR_MICROBLAZE_0_USE_FPU == 1
	{
		xRegisterDump.ulFSR = mffsr();
	}
	#else
	{
		xRegisterDump.ulFSR = 0UL;
	}
	#endif

	/* Also fill in a string that describes what type of exception this is.
	The string uses the same ID names as defined in the MicroBlaze standard
	library exception header files. */
	switch( ( uint32_t ) pvExceptionID )
	{
		case XEXC_ID_FSL :
				xRegisterDump.pcExceptionCause = ( int8_t * const ) "XEXC_ID_FSL";
				break;

		case XEXC_ID_UNALIGNED_ACCESS :
				xRegisterDump.pcExceptionCause = ( int8_t * const ) "XEXC_ID_UNALIGNED_ACCESS";
				break;

		case XEXC_ID_ILLEGAL_OPCODE :
				xRegisterDump.pcExceptionCause = ( int8_t * const ) "XEXC_ID_ILLEGAL_OPCODE";
				break;

		case XEXC_ID_M_AXI_I_EXCEPTION :
				xRegisterDump.pcExceptionCause = ( int8_t * const ) "XEXC_ID_M_AXI_I_EXCEPTION or XEXC_ID_IPLB_EXCEPTION";
				break;

		case XEXC_ID_M_AXI_D_EXCEPTION :
				xRegisterDump.pcExceptionCause = ( int8_t * const ) "XEXC_ID_M_AXI_D_EXCEPTION or XEXC_ID_DPLB_EXCEPTION";
				break;

		case XEXC_ID_DIV_BY_ZERO :
				xRegisterDump.pcExceptionCause = ( int8_t * const ) "XEXC_ID_DIV_BY_ZERO";
				break;

		case XEXC_ID_STACK_VIOLATION :
				xRegisterDump.pcExceptionCause = ( int8_t * const ) "XEXC_ID_STACK_VIOLATION or XEXC_ID_MMU";
				break;

		#if XPAR_MICROBLAZE_0_USE_FPU == 1

			case XEXC_ID_FPU :
						xRegisterDump.pcExceptionCause = ( int8_t * const ) "XEXC_ID_FPU see ulFSR value";
						break;

		#endif /* XPAR_MICROBLAZE_0_USE_FPU */
	}

	/* vApplicationExceptionRegisterDump() is a callback function that the 
	application can optionally define to receive the populated xPortRegisterDump
	structure.  If the application chooses not to define a version of 
	vApplicationExceptionRegisterDump() then the weekly defined default 
	implementation within this file will be called instead. */
	vApplicationExceptionRegisterDump( &xRegisterDump );

	/* Must not attempt to leave this function! */
	for( ;; )
	{
		portNOP();
	}
}
/*-----------------------------------------------------------*/

void vPortExceptionsInstallHandlers( void )
{
static uint32_t ulHandlersAlreadyInstalled = pdFALSE;

	if( ulHandlersAlreadyInstalled == pdFALSE )
	{
		ulHandlersAlreadyInstalled = pdTRUE;

		#if XPAR_MICROBLAZE_0_UNALIGNED_EXCEPTIONS == 1
			microblaze_register_exception_handler( XEXC_ID_UNALIGNED_ACCESS, vPortExceptionHandlerEntry, ( void * ) XEXC_ID_UNALIGNED_ACCESS );
		#endif /* XPAR_MICROBLAZE_0_UNALIGNED_EXCEPTIONS*/

		#if XPAR_MICROBLAZE_0_ILL_OPCODE_EXCEPTION == 1
			microblaze_register_exception_handler( XEXC_ID_ILLEGAL_OPCODE, vPortExceptionHandlerEntry, ( void * ) XEXC_ID_ILLEGAL_OPCODE );
		#endif /* XPAR_MICROBLAZE_0_ILL_OPCODE_EXCEPTION*/

		#if XPAR_MICROBLAZE_0_M_AXI_I_BUS_EXCEPTION == 1
			microblaze_register_exception_handler( XEXC_ID_M_AXI_I_EXCEPTION, vPortExceptionHandlerEntry, ( void * ) XEXC_ID_M_AXI_I_EXCEPTION );
		#endif /* XPAR_MICROBLAZE_0_M_AXI_I_BUS_EXCEPTION*/

		#if XPAR_MICROBLAZE_0_M_AXI_D_BUS_EXCEPTION == 1
			microblaze_register_exception_handler( XEXC_ID_M_AXI_D_EXCEPTION, vPortExceptionHandlerEntry, ( void * ) XEXC_ID_M_AXI_D_EXCEPTION );
		#endif /* XPAR_MICROBLAZE_0_M_AXI_D_BUS_EXCEPTION*/

		#if XPAR_MICROBLAZE_0_IPLB_BUS_EXCEPTION == 1
			microblaze_register_exception_handler( XEXC_ID_IPLB_EXCEPTION, vPortExceptionHandlerEntry, ( void * ) XEXC_ID_IPLB_EXCEPTION );
		#endif /* XPAR_MICROBLAZE_0_IPLB_BUS_EXCEPTION*/

		#if XPAR_MICROBLAZE_0_DPLB_BUS_EXCEPTION == 1
			microblaze_register_exception_handler( XEXC_ID_DPLB_EXCEPTION, vPortExceptionHandlerEntry, ( void * ) XEXC_ID_DPLB_EXCEPTION );
		#endif /* XPAR_MICROBLAZE_0_DPLB_BUS_EXCEPTION*/

		#if XPAR_MICROBLAZE_0_DIV_ZERO_EXCEPTION == 1
			microblaze_register_exception_handler( XEXC_ID_DIV_BY_ZERO, vPortExceptionHandlerEntry, ( void * ) XEXC_ID_DIV_BY_ZERO );
		#endif /* XPAR_MICROBLAZE_0_DIV_ZERO_EXCEPTION*/

		#if XPAR_MICROBLAZE_0_FPU_EXCEPTION == 1
			microblaze_register_exception_handler( XEXC_ID_FPU, vPortExceptionHandlerEntry, ( void * ) XEXC_ID_FPU );
		#endif /* XPAR_MICROBLAZE_0_FPU_EXCEPTION*/

		#if XPAR_MICROBLAZE_0_FSL_EXCEPTION == 1
			microblaze_register_exception_handler( XEXC_ID_FSL, vPortExceptionHandlerEntry, ( void * ) XEXC_ID_FSL );
		#endif /* XPAR_MICROBLAZE_0_FSL_EXCEPTION*/
	}
}

/* Exclude the entire file if the MicroBlaze is not configured to handle
exceptions, or the application defined configuration item 
configINSTALL_EXCEPTION_HANDLERS is not set to 1. */
#endif /* ( MICROBLAZE_EXCEPTIONS_ENABLED == 1 ) && ( configINSTALL_EXCEPTION_HANDLERS == 1 ) */